In the U.S., any substance the intended use of which results in its migrating to food is considered a food additive. In the situation you describe, the printing ink falls under the definition of a "food additive," if it is reasonable expected to migrate into the candy with which it is in contact. Unless the ink is covered by a food additive regulation, an effective Food Contact Notification (FCN), a Threshold of Regulation exemption letter, or is generally recognized as safe (GRAS), the confectionery could be considered adulterated. However, in situations where no migration of the ink to the food is expected (i.e., when a functional barrier exists), the ink is not considered a food additive and a regulatory clearance is not required, provided it is safe for the intended use. "No migration" may be demonstrated by migration testing through the use of models that estimate migration.

In India, The Food Safety and Standards Act, 2006, defines a "contaminant" as "any substance, whether or not added to food, which is present in such food as a result of the production …, manufacture, processing, preparation, treatment, packing, packaging, …" To establish a suitable status for the use in food packaging of a specific ink, you would need to consult with qualified legal counsel.